PPARgamma, PTEN, and the Fight against Cancer.

Peroxisome proliferator-activated receptor gamma (PPARgamma) is a ligand-activated transcription factor, which belongs to the family of nuclear hormone receptors. Recent in vitro studies have shown that PPARgamma can regulate the transcription of phosphatase and tensin homolog on chromosometen (PTEN), a known tumor suppressor. PTEN is a susceptibility gene for a number of disorders, including breast and thyroid cancer. Activation of PPARgamma through agonists increases functional PTEN protein levels that subsequently induces apoptosis and inhibits cellular growth, which suggests that PPARgamma may be a tumor suppressor. Indeed, several in vivo studies have demonstrated that genetic alterations of PPARgamma can promote tumor progression. These results are supported by observations of the beneficial effects of PPARgamma agonists in the in vivo cancer setting. These studies signify the importance of PPARgamma and PTEN's interaction in cancer prevention.